Roberto Di Pietro, Luigi V. Mancini and

waralligatorΚινητά – Ασύρματες Τεχνολογίες

21 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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Roberto Di Pietro, Luigi V. Mancini and
Alessandro Mei


Limited memory


Limited computational power


Limited energy



Passive attacks


Cipher text attacks


Active attacks


Take control of a sensor node



Unfriendly environment


Nodes only trust themselves


Secure pairwise communication


Memory efficient


Energy efficient


Tolerate the collusion of a set of corrupted
sensors


Have one master key


Can’t tolerate nodes being taken over


Each node stores a seperate key for every
other node


Requires too much space


Expensive to add more nodes later


Tradeoff


Use less memory, but have only a probabilistic
tolerance to nodes being taken over


One way hash function


Symmetric encryption


Keyed hashed function


Pseudo
-
random number generator



A key deployment scheme


A key discovery procedure


A security adaptive channel establishment
procedure

Method used in
A key
-
management

scheme for distributed sensor networks
:



A pool of P random keys is generated


Each sensors takes k random keys from the
pool


Challenge is encrypted using each key and
then broadcasted


Needs to perform k^2 decryptions on receiver
side and k encryptions on the sender side


At least k messages have to be sent


Also used in
A key management scheme for
distributed sensor networks



Instead of challenge response, submit the
indexes


Less secure, as a smart attacker can easily
find the nodes that have the key it wants

Method used in
Establishing pair
-
wise keys for

secure communication in ad hoc networks: A

probabilistic approach:


A pool of P random keys is generated


k indexes into the pool are created pseudo
-
randomly with a publicly known seed
dependent on the node id.


Less secure than challenge
-
response, but can
be improved



Find out which keys are shared and xor them
together


An attacker needs to know all shared keys


Nearby sensors


Weaker against geographically attacks


Random


Larger communication overhead


Individual properties


More trusted nodes can give higher security


They give an upper bound on the probability
that the channel between two nodes is
corrupted, given w corrupted nodes


Sensor failure resistent


Can add more sensors if required


No information leakage


Sensors in the C set only transmits hash values of
their keys


Adaptiveness


If an upper bound of w is known, C can be chosen to
secure communication with a desired probability.


Load balance


a sends c+1 message, sensors in C send 1, tot=2c+1


Only done once during setup


Sensor doesn’t respond


After timeout, node a can pick another node


Sensor sends correct key


Lowers security


Sends false key


Can pick another C set


Notify trusted base
-
station


Aware that network is under attack


If node a has the keys that node a should
have, according to the pseudo
-
random
number generator, it’s probable that a is a.


M = {}


for all keys k in P


z = RND(id||k)


if(z%(|P|/m)==0)


put k into M



|M| must be less than memory size

but larger
than the security constraints


Discard ID if conditions not satisfied